1. Field of the Invention
The present invention relates generally to a terminal crimping apparatus for caulking, in a connector housing, a so-called crimped terminal loaded in the connector housing to crimp the crimped terminal against an end of an electric wire.
2. Description of the Related Art
As a terminal for electrically connecting electric wires to each other, a so-called press-connecting terminal and a crimped terminal have been generally known. The press-connecting terminal is of such a type as to pinch a conductor of an electric wire between a pair of blade parts integrally extend from the terminal so as to electrically connect the terminal with the conductor by the pinching force. Press-connecting terminal is mainly used for a weak current. On the other hand, the crimped terminal is such a type as to previously strip a conductor in an end of an electric wire and crimp a pair of wire barrels so provided as to integrally extend from the terminal in a predetermined configuration to electrically connect the stripped conductor and the terminal to each other. Crimped terminal is mainly used for a strong current.
The crimped terminal has higher tensile strength and is more reliably rendered conductive as compared with the press-connecting terminal, so the crimped terminal is widely employed in the field in which reliability is required.
The present invention is suitable for a crimping connector of such a type as to electrically connect the above described crimped terminal and the electric wire to each other inside a connector housing. Such a crimping connector has been already widely provided (see, for example, Japanese Patent Laid-Open Gazette No. 1-232680 and Japanese Patent Laid-Open Gazette No. 3-165478).
This crimping connector is provided with openings 101 and 102 formed in opposite sides of a connector housing 100. Openings 101 and 102 are so covered with covers 103 and 104 that they can be opened and closed, as shown in FIGS. 3A and 3B. A plurality of crimped terminal inserting portions 105 are provided side by side inside the connector housing 100. In this crimping connector, a wire barrel A1 is caulked into a predetermined configuration as shown in FIG. 3A or 3B by a terminal crimping apparatus as described later. In an caulking operation of the terminal crimping apparatus, a crimped terminal A is loaded in each of the crimped terminal inserting portions 105 and a conductor W1 of an electric wire W is stripped to be joined to the crimped terminal A, thereby to make it possible to crimp the wire barrel A1 against the conductor W1 in an end of the electric wire W. An insulation barrel A2 of the crimped terminal A is also pressed by the apparatus at a time in a state where the barrel A2 is received by the bottom of the connector housing 100, thereby to make it possible to crimp the insulation barrel A2 against a coated end W2 of the electric wire W.
Such a crimping connector has the advantage that crimping work of the electric wire W and the crimped terminal A can be easily and quickly performed, and is significantly suitable particularly in automating the fabrication of a wiring harness.
The above described terminal crimping apparatus comprises an anvil 107 and a crimper 108 disposed in close proximity to each other and are so opposed to each other as to interpose a connector housing 100 therebetween, as shown in FIG. 4. The tip of the anvil 107 is introduced into a crimped terminal inserting portion 105 of the connector housing 100 and the crimper 108 is lowered by pressing means from above state, thereby to make it possible to interpose and caulk a wire barrel A1 of a crimped terminal A between the crimper 108 and the anvil 107.
In a wiring harness for, for example, an automobile which is repeatedly subjected to violent vibration, a wire barrel A1 of a crimped terminal A must be very firmly crimped against a conductor W1 of an electric wire W so as to reliably maintain conduction between the conductor W1 of the electric wire W and the crimped terminal A for a long time period. In the terminal crimping apparatus of the above described construction, however, a clearance S is formed between the crimper 108 and the anvil 107, thereby making it impossible to obtain the desired connecting intensity because the crimped terminal A escapes to the clearance S even if pressure applied to the crimper 108 is increased.
Meanwhile, in general crimping of a terminal against an electric wire for a large current, a terminal crimping apparatus is used for crimping a terminal without forming the above described clearance S (see, for example, Japanese Patent Laid-Open Gazette No. 98278/1991).
As shown in FIG. 5, such a terminal crimping apparatus is provided at a lower part of a crimper 108 with a substantially U-shaped surrounding portion 108a which receives an anvil 107 with no clearance in order to surround the crimped terminal A with no clearance, and so adapted that the crimper 108 is pressed by applying high pressure for ensuring the desired connecting intensity to decrease the contact resistance in a crimped portion. This type of terminal crimping apparatus cannot be applied to a crimping connector for crimping a terminal in a housing as described above due to the following problem. Specifically, in a crimping connector used for a wiring harness, the width of the crimped terminal inserting portion 105 is narrow, as shown in FIG. 3. Consequently, an attempt to use the terminal crimping apparatus shown in FIG. 5 is interrupted by the surrounding portion 108a having a large wall thickness t. If this surrounding portion 108a were thin, the intensity of the surrounding portion 108a would be insufficient: the surrounding portion 108a would be spaced farther apart in caulking the crimped terminal A, so that a clearance would be formed between the crimper 108 and the anvil 107. Consequently, it is difficult to actually apply the terminal crimping apparatus to crimping of a terminal in a crimping connector.